Work is planned on two topics. (1) A theoretical simulation of problem solving in geometry is planned, with the intention of representing interactions between spatial and verbal reasoning processes of understanding in a system where different amounts of knowledge can be included to test hypotheses about learning. Features of this system will be guided by protocols obtained from students during their study of geometry, and experiments conducted to test hypotheses about planning processes and perception of problem materials. (2) Studies of components of analogical reasoning will be conducted, especially processes of perceiving and identifying relations between stimuli.